Staple for stapling machines



` Filed ngc. 2s. `195o Aug. 24, 1954 w. DRYPoLcHl-:R' 2,687,061 STAPLE FOR STAPLING MACHINES 2 Sheets-Sheet l i Aug. Z4, 1954 W. DRYPOLCH ER VSI'PLE FOR STAPLING MACHINES 2,687,061 Filed Dec. 23, 1950 2 Sheets-Sheet 2 Hal/- Patented Aug. 24, 1954 2,687,061 S'TAPLE FOR STAPLING MACHINES William Drypolcher, Valley Stream, N.

Lou Obstfeld, Brooklyn, and Abraham signor to Obstfeld, New York, N. Y.

Application December 23, 1950,

2 Claims.

'I'his invention relates to the art of stapling, and more particularly to an improved staple for use in an improved stapling machine.

The primary object of my invention is to genas are usually cemented together side by side to form a channebshaped stick or bar of staples. 1

A more specic object is to avoid jamming of staples in the staple magazine. Such a jam prevents further feed of staples by the staple feed This staple was intended to feed jams resulting from rotaof the material after it leaves the forming dies. There are also` irregularities in the thickness of the metal used.

To accomplish the foregoing objects, and other which will hereinafter apscribed in the specification and sought to be dened in the claims. The specification is accompanied `by drawings, in which:

Serial No. 202,535

Fig. 1 is a partially sectioned side elevation of a stapling machine embodying features of my invention;

Fig. 2 is a front elevation of features of my invention;

Fig. 3 Iis a transverse section taken approximately in the plane of the line 3-3 of Fig. 1;

Fig. 4 is a fragmentary section longitudinal of the magazine taken approximately in the plane ofthe line 4-4 of Fig. 3;

Fig. 5 is a section similar to Fig. 3, but eX- planatory of the operation of the invention;

Fig. 6 is a section similar to Fig. 4 and is explanatory of a feature of the invention;

Fig. 7 is a section taken approximately in the plane of the line 1-7 of Fig. 6;

Fig. 8 is a perspective view showing parts of the machine including a wear plate used at the forward end;

Fig. 9 is a partially sectioned side elevation like a part of Fig. 1, but drawn to enlarged scale;

Fig. 10 is a similar View showing the relation of the parts when only one staple remains in the machine;

Figs. 11 and 12- show an earlier staple before and after straightening of the slope leg;

Figs. 13 and 14 show the present staple before and after straightening of the slop leg;

Fig. 15 shows the staple in relation to the staple drive channel; and

Fig. 16 is a View generally similar to Fig. 15 but showing a modiiication.

Referring to the drawing, and more particularly a staple embodying Referring now to Fig. 2 of the drawing, the staple of my invention has pending from the crown 24. In preferred form the leg 26 is perpendicular to the crown, or rather to a horizontal line representing the average or mean position of t e crown. The other leg 28 slopes at an angle to the perpendicular.

face-to-face relation to form a staple bar or stick. The slope of the leg 28 may range from five to thirty degrees from the perpendicular, and preferably has a slope in the range of from ten to fteen degrees.

The advantage of the sloping or sprung leg is fully explained in the previously mentioned Patent 2,421,429 to Obstfeld, but briefly, and with reference to Figs. 5, 6 and 7, it may be explained that in the event of turning of a staple about its crown, as indicated at 3d in Fig. 6, the staple can turn is strictly limited, for the reason that the width of the staple at the lower end of the sloping leg 2B is wider than the upper part of the magazine. In other words, as the tip 32 of the staple rises it reaches the outer wall 34, of the magazine, as is best shown in Fig. 7, which prevents further turning of the staple. When it can turn only a limited amount, say less than forty-five degrees, the pressure of the staple pusher moves the staple back into desired upright position.

Referring now to Figs. 3 and d, the staple magazine comprises a staple core 36 and an outer wall 38 with a staple guide passage therebetween. The top portion d!) of the staple core is shaped to receive the concave crown 2d of the staples. This may be done by bending the material of the core, or by cutting away the top wall of the core, or part of each as here shown. The outer wall 38 is left straight.

The staple pusher d2 is made of sheet metal bent to fit around the staple core 3S. The top forward edge is of the pusher is not depressed or concave like the staple crown, but instead is straight. It normally bears against only the end portions of the crown, as shown in Figs. 3 and 4.

Because of the preferably generous clearance in the staple magazine a loose staple may sometimes rise somewhat from the staple core, as is indicated by the lifted crown 2d in Fig. 5 of the drawing. With a straight crown as heretofore employed this situation has sometimes led to staple jams because the rather strongly pressed pusher 42 will tend to wedge beneath the staple. lt will be evident from inspection of Fig. 5, however, that this cannot occur with the depressed crown 2d, for even when the ends of the crown rise from the staple core 36 the center portion of the crown still is low enough to come in front of the straight, forward edge of the pusher. rlhus by using a downwardly offset crown, in addition to the sloping leg, staple feed jams are avoided whether caused by a loose staple in the middle of the staple stick, or at one end of the staple stick.

The pusher is preferably provided with means to prevent rising, and in the present case this takes the form of a pair of flanges it bent inwardly at the bottom of the pusher beneath the staple core 35. These flanges hold the pusher on the core and, of course, a similar result may be obtained in other ways, for example by providing a yieldable projection or tongue at the top of the pusher to ride resiliently against the bottom face of the top outer wall 38 of the magazine. The selection of the particular means to inhibit rising of the pusher depends to a large extent on the surrounding structure of the stapling machine, for if the staple core is secured directly to an outer wall at the bottom of the stapling arm it would not be feasible to use inturned flanges at the bottom.

There are three kinds of which often work to counteract one another tolerance involved but which in some cases may all add in one direction. One has to do with the thickness of the material itself. Another results from the forming or pressing operations in the dies. The third results during assembly. The assembly tolerance sometimes may amount to more than the material tolerance plus the operations tolerance combined.

rIhe staple core 36 is formed out of sheet metal which is much thinner than the outside wall 38 of the staple magazine. The staple pusher 42 may also be made of relatively thin sheet metal. With this thin material the material tolerance and the pressing operation tolerance are much smaller than is the case with thick metal. It is therefore entirely feasible to make the pusher l2 lit the core 36 far more accurately than the ht of the staple in the magazine, for a similar close tolerance cannot readily be provided between the core and the outside wall 38, the latter being made of heavy sheet metal. Also the assembly tolerance between relatively long major parts, such as the core and the outside wall S8, is greater than the assembly tolerance in a subassembly involving only the staple pusher and the core.

Referring now to Figs. 8, 9 and 10 of the drawing, the staple core `3@ receives staples 5t which are urged forward by staple pusher if previously referred to, under the inuence of a compression spring behind the pusher, but not shown. The outer wall or housing of the staple arm is indicated at 3S. At its forward end the stapling arm is provided with a wear plate 561, and it will be understood that when the parts of the machine are assembled the forward end of core 36 substantially abuts the wear plate bil. The wear plate has a slot with a straight leg portion 5G, a sloping leg portion 523, and a concave top portion these being shaped and dimensioned to freely pass the staples tii. However, because of the concave slot 'lili and the straight, forward top edge of the pusher d2, the pusher cannot pass the front wear plate 5d, and instead is arrested against further movement. rThis is illustrated by the change from Fig. 9 to Fig` l0. In Fig. 9 the pusher d2 bears against staples 5i) and urges them into the staple driving slot 62 where the endmost staple comes beneath staple driver 20. When the staples have been used the last staple, indicated at Si in Fig. l0, remains in the wear plate 515i, the pusher being arrested in the position :l2 with its front edge behind the wear plate.

The wear plate is preferably made of material having approximately the same gauge or thickness as the width of a staple, so that one staple remains unfed at the end of the clip. Because of the concave shape of the slot in the wear plate, contrasted with the straight shape of the forward top edge of the pusher, the wear plate pre,- vents the pusher from moving further, and thus no additional means is needed to guard against the possibility of the pusher moving so far forward as to enter the drive channel where it could be damaged by the staple driving blade.

If desired the front wear plate may be arranged to form a yieldable staple drive channel, generally as disclosed in my Patent 2,289,397 issued July '7, 1942, and entitled Stapling Machine. For that purpose the wear plate 59; is formed integrally with a top member which is pressed downward by a compression spring 68 (Fig. 9). This urges plate 5d forward about corner 55, but there is clearance at El. The plate` may be anchored by lugs 59 struck downwardly fromr top means to prevent scribed the pusher as including means is not es- 1t from rising the use of such The possible explanation is that when the staple stick has become short the downit from rising.

The combination of the concave crown and the sloping leg has particular advantages.

slope leg is cammed inward to perpendicular position by means indicated in Fig. 15, which shows the staple drive channel 12 enlarged at 14 to receive the stable 16, and having a cam surface at cave crown as indicated at 24', but vex the crown.

Moreover, the fact that the outward sprung legis cammed straight results in a snug fit of the staple legs in the drive channel to get maximum penetrating power. The fact that the crown of to" the upper ends of the leg portions of the staple, and

erally like that shown in Fig. 15, omits the camming surface 18. This permits the staple to be driven with its leg in spread condition. I have found that the present staple solid material ing claims.

I claim: 1. A staple for use in a magazine type stapling machine having a sloping staple guide passage to References Cited in the le of this patent UNITED STATES PATENTS 

